This invention pertains to a dosage form that provides a delivery of drug over an extended period of time. More particularly, the invention concerns a dosage form that provides a known and constant drug-release pattern for an indicated therapy. The invention also relates to a dosage form that provides a controlled, constant and uniform delivery of a known dose of drug over time.
A critical need exists for a dosage form for the controlled and uniform administration of a drug for therapy over time. Presently, in the practice of pharmacy and medicine a drug is administered in conventional pharmaceutical forms, such as tablets and capsules. These conventional forms deliver their drug by dumping, which leads to uneven dosing of drug and uneven blood levels of drug, characterized by peaks and valleys. Accordingly, this does not provide controlled and uniform therapy over time.
The prior art provides dosage forms for continuous therapy. For example, in U.S. Pat. No. 4,327,725, issued to Cortese and Theeuwes, and in U.S. Pat. Nos. 4,612,008, 4,765,989 and 4,783,337, issued to Wong, Barclay, Deters and Theeuwes, a dosage form is disclosed that provides therapy by generating an osmotic pressure inside the dosage form. The dosage form of these patents operates successfully for delivering a drug for a preselected therapy. With the delivery of some drugs, however, these dosage forms often exhibit erratic release rate patterns, such as a non-uniform variation in the drug release rate, and the dosage form can stop delivering a drug; that is, the dosage form can shut down intermittently.
In view of the above presentation, it is immediately apparent that an urgent need exists for a reliable dosage form. The need exists for a dosage form endowed with properties for delivering a drug at a known and uniform rate over time. The need also exists for a dosage form free of deviation in its release-rate profile, which delivers the needed dose of drug with a reduced amount of drug left in the dosage form at the end of the delivery period. It will be appreciated by those knowledgeable in the drug-dispensing art that if a novel and unexpected dosage form is made available that provides a uniform and known drug-release profile free of the tribulations of the prior art, such a dosage form would represent an advancement and a valuable contribution in the drug dispensing art.
Accordingly, in view of the above presentation it is an immediate object of the invention to provide a dosage form that delivers a drug in an uniform dose to a biological, drug-receiving environment over an extended drug-delivery therapy time.
Another object of the invention is to provide a novel dosage form that avoids administering a drug in a non-uniform and varying rate, and therefore exhibits substantially the same dose-dispensing rate over time.
Another object of the invention is to provide a dosage form that delivers a predetermined and prescribed dose in the same manner over time, while simultaneously lessening the amount retained or the residual drug left in and not delivered from the dosage form.
Another object of the invention is to provide a drug composition of matter comprising drug particles of 5 to 150 xcexcm (microns) and hydrophilic polymer particles of 5 to 250 xcexcm, characterized by the drug particles and the hydrophilic polymer particles functioning together to provide a uniform and nonvarying rate of release of both, which is free of a deviation and free of a decrease in the rate of the release over time.
Another object of the invention is to provide a dosage form comprising a membrane that surrounds a drug core comprising drug particles of 1 to 150 xcexcm and hydrophilic polymer particles of 1 to 250 xcexcm, which are codelivered from the dosage form through an exit formed by a process selected from the group consisting of a drilled exit, a bioerosion exit, a leaching exit, a solubilizing exit and an exit formed by rupture.
Another object of the invention is to provide a dosage form comprising a membrane comprising a semipermeable composition that surrounds a core comprising a drug layer comprising drug particles of 1 to 150 xcexcm and polymer particles of 1 to 250 xcexcm, and a displacement layer comprising an osmopolymer hydrogel that imbibes fluid, hydrates and increases in swelling volume, thereby displacing the drug layer through an exit selected from the group consisting of an orifice, a passageway, a pore, a microporous channel, a porous overlay, a porous insert, a micropore, a microporous membrane and a porepassageway.
Another object of the invention is to make available a process for providing a uniform and nonvarying drug delivery program from a dosage form, wherein the process comprises the steps of selecting drug particles of 1 to 150 xcexcm; selecting hydrophilic polymer particles of 1 to 250 xcexcm; blending the selected particles into a drug-polymer core; and surrounding the core with a membrane comprising means for delivering the drug from the core in a uniform and nonvarying rate of release over a period of time up to 30 hours.
Another object of the invention is to provide a dosage form for delivering a drug to human, wherein the dosage form comprises a drug composition comprising 0.05 ng to 1.2 g of drug having a particle size of 1 to 150 xcexcm, and a hydrophilic polymer having a particle size of 1 to 250 xcexcm; a push composition that imbibes fluid and expands for pushing the drug composition from the dosage form; a wall that surrounds the drug and the push composition that is permeable to the passage of fluid; an inner coat that surrounds the drug and push compositions, positioned between the inside surface of the wall and the drug and push compositions, for governing fluid imbibition into the drug and push compositions for 30 minutes to 4 hours and 30 minutes; and at least one exit means in the wall for delivering the drug composition at a uniform and nonvarying rate over time.
Other objects, features and advantages of the invention will be more apparent to those versed in the dispensing art, comprising medicine and pharmacy, from the following detailed specification taken in conjunction with the accompanying claims.